Fan blade

ABSTRACT

The present invention relates to a fan impeller structure, which includes a hub having a plurality of blades distributed around the periphery of the hub in a radial manner. The blade has a windward surface and a leeward surface; at least a flow-guiding section is disposed on the leeward surface and is preferably located near the end portion of the outer edge of the blade and is mounted in parallel to the radial direction of the fan impeller. Therefore, when air is sucked in from the top and bottom sides of the blade respectively, the heat-dissipation performance loss resulting from the mutual collision of the air flow is avoided due to the flow-dividing and flow-guiding effect of the flow-guiding section.

FIELD OF THE INVENTION

The present invention relates to a fan impeller structure, and more particularly to a practical structure having flow-dividing and flow-guiding blades that improve the turbulence near the leeward side of the conventional blades to reduce air resistance and enhance air flow quantity and operating efficiency.

BACKGROUND OF THE INVENTION

As shown in FIG. 1 and FIG. 2, a conventional fan impeller structure includes a hub 10 having a plurality of blades 11 arranged in a radial manner around the periphery of the hub 10. When the fan impeller is driven by a motor (not shown), the surrounding air is driven to form a flow field as a result of the rotation of the fan impeller.

Together with the illustration of FIG. 2 and FIG. 3, each blade 11 of the fan impeller has a windward surface 12 and a leeward surface 13. When the fan impeller rotates, air is pushed by the windward surface 12 of the blade 11 such that the pressure adjacent to the leeward surface 13 of the blade 11 is abruptly dropped to form a zone of negative pressure. To achieve the pressure balance, the zone of negative pressure will suck in its surrounding air and is subjected to the thrust of the windward surface 12 of next blade 11 to form a cycle.

Whereas, after the zone of negative pressure of the aforementioned fan impeller sucks in its surrounding air, the air sucked in from the top and bottom sides of the blade 11 respectively will meet at the end portion of the leeward surface 13 to form a turbulence zone 14, and due to continuous collision and counterbalancing effect the air flow inside the turbulence zone 14 results in eddies and noises which lowers the air flow quantity and affects the heat-dissipation performance.

SUMMARY OF THE INVENTION

In view of the foregoing concern, the present invention thus provides a fan impeller structure that targets at solving the turbulence in the proximity of the leeward surfaces of the blades of the conventional fan impeller structure, thereby smoothening the flow field to reduce the air resistance and increase the air flow quantity.

The fan impeller includes a hub having a plurality of blades stretched in a radial manner around the periphery of the hub, in which each blade has a windward surface and a leeward surface, at least one flow-guiding section is disposed on the leeward surface, and the flow-guiding section is preferably located near the end portion of the outer edge of the blade and is mounted in a direction which is parallel to the radial direction of the fan impeller, such that the leeward surface of the blade is divided into an upper portion and a lower portion by the flow-guiding section.

Consequently, when air is sucked in from the top and bottom sides of the blade respectively, eddies, noises and efficacy loss resulting from mutual collision and counteraction of air flow can be avoided due to the flow-dividing and flow-guiding functions of the flow-guiding section, and the wind shear acted on the blade is alleviated, so as to enhance the stability and achieve the optimized heat-dissipation effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic top view showing a conventional fan impeller structure;

FIG. 2 is a schematic side view showing the conventional fan impeller structure;

FIG. 3 is a schematic flow field driven by the blade of the conventional fan impeller structure;

FIG. 4 is a schematic view showing the three-dimensional appearance of the present invention;

FIG. 5 is a schematic top view of the present invention;

FIG. 6 is a schematic side view of the present invention;

FIG. 7 is a schematic view showing the flow field driven by the blades of the present invention; and

FIG. 8 is a schematic view showing the flow field driven by the blades of another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

To make the object, features and efficacy of the present invention more comprehensive, preferred embodiments of the present invention are enumerated along with the detailed illustrative description.

Please also refer to FIG. 4 and FIG. 5. The fan impeller structure therein includes:

a hub 20 having a plurality of blades 21 distributed in a radial manner around the periphery of the hub 20, in which the blades 21 are selected from either type of axial-flow blade or blower blade (the one shown in FIG. 4 and FIG. 5 pertains to a blower blade), each blade 21 has a windward surface 22 and a leeward surface 23, and at least a flow-guiding section 24 is mounted on the leeward surface 23 and is preferably located near the end portion of the outer edge of the blade 21 and is mounted in parallel to a radial direction of the fan impeller such that the leeward surface 23 of the fan blade 21 is divided into an upper portion and a lower portion by the flow-guiding section.

Further refer to FIG. 6 and FIG. 7. When the fan impeller is driven by a motor (not shown), its surrounding air is driven to form a flow field due to the rotation of the fan impeller. After air is sucked in a zone of negative pressure in the proximity of the leeward surface of the blade, the air sucked in from the top and bottom sides of the blade 21 respectively, due to the flow-dividing and flow-guiding effect of the flow-guiding section 24, flows in a way more closely attached the surface of the blade 21, so as to avoid eddies and noises arising from mutual flow collision and counteraction at the same time.

Moreover, when air is closely flowing along the surface of the blade 21, on the one hand, it will generate an thrust on the blade 21, and on the other hand, it can alleviate the wind shear effect acted on the blade 21 to enhance its stability, thereby providing the optimized heat-dissipation performance.

Besides, please refer to FIG. 8. An arc-like flow-guiding angle is designed on the flow-guiding section 25 and over the intersection of the flow-guiding section 25 and a blade 21 respectively, making air flow in a way more easily attached to the surface of the blade 21 to prevent the occurrence of small turbulence.

In sum, by means of the design of the flow-guiding section 24 on the leeward surface 23 of the blade 21 of the fan impeller in the present invention, the mutual collision and counteraction of the air sucked in from the top and bottom sides of the blade 21 respectively can be avoided due to the flow-dividing and flow-guiding effect of the flow-guiding section 24, so as to maintain the normal air flow quantity and the heat-dissipation performance of the blade. From the above-mentioned characteristics those features not only have a novelty among similar products and a progressiveness but also have an industry utility.

While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. 

1. A fan impeller structure, comprising: a hub; a plurality of blades disposed in a radial manner around a periphery of said hub; a windward surface and leeward surface located on each said blade; and at least one flow-guiding section disposed on said leeward surface.
 2. The fan impeller structure of claim 1, wherein said at least one flow-guiding section is located near an end portion of an outer edge of said blade and is mounted in parallel to a radial direction of said fan impeller to divide said leeward surface of said blade into an upper portion and a lower portion.
 3. The fan impeller structure of claim 1, wherein an arc-like flow-guiding angle is formed on said flow-guiding section and over an intersection of said flow-guiding section and said blade respectively.
 4. The fan impeller structure of claim 1, wherein said blade is selected from one type of axial-flow blade and blower blade. 